Built in a truly React.js way this navbar is totally customisable via props, all the links, items, colors, sizes, logo, etc are passed through props. And it has dropdowns as well!
Check it out for your next project, it will save a lot of time.
This is a super beginner-friendly introduction made by BCS for the Google I/O 2018 extended talks. An 8-step process, in every step new stuff being added and marked with comments in the html or css file.